• Looking for a smarter way to manage your heating this winter? We’ve been testing the new Aqara Radiator Thermostat W600 to see how quiet, accurate and easy it is to use around the home. Click here read our review.

Two PIRs to one set of lights.

It does work, albeit with a bit of a quirk. The requirement is for the lights to be on if either PIR is on. To avoid any interaction between the two PIRs, the relay contacts must be break-before-make (which most are). This means that if PIR2 times out while PIR1 is still on, there will be a momentary loss of power while the contacts change over. You might not like this. Personally I would go for the more elegant solution with two single pole relays.

I don't think I can upload pictures from here so I'll just have to describe it. Each PIR controls one relay coil, possibly with a small lamp in parallel. Check your PIRs for any minimum load requirement. The contacts of the two relays are connected in parallel and, together, they switch the main lights from a permanent live supply.

PS: mr_chaela's solution does have one advantage; there's no need to connect an extra lamp to PIR1.
 
breezer said:
as i said
breezer said:
when pir 2 turns off it will then put the supply back on turning the lights back on.

not really what the OP wants

But PIR1 would have timed out by then (assuming both PIR's have the same time setting), the only time the lights would stay on is if PIR1 has been re-activated by someone walking past or until it timed out as set - which is what is wanted.

With regards the lights flickering when PIR2 takes over, relay contacts operate pretty damn quickly (we're talking milliseconds here), the momentary dimming of the light probably wont be noticeable
 
i dissagree.

as i said when pir 2 "times out" it then puts the supply back onto pir1.

pir1 has now been off for some time (the duration of pir 2 on time) this means that pir 1 will now put the lights on for its set time since it has now got a supply that it didnt have say 2 minutes ago.

any mains pir will when first powered up turn the lights on, which is what your idea will do
 
breezer said:
i dissagree.

as i said when pir 2 "times out" it then puts the supply back onto pir1.

pir1 has now been off for some time (the duration of pir 2 on time) this means that pir 1 will now put the lights on for its set time since it has now got a supply that it didnt have say 2 minutes ago.

any mains pir will when first powered up turn the lights on, which is what your idea will do

I think you misunderstand, the circuit is not switching the supply to the PIR, it's switching the output from the PIR
 
mr_chaela said:
I think you misunderstand, the circuit is not switching the supply to the PIR, it's switching the output from the PIR

your drawing did not make that bit clear, but yes, now you mentioned that bit....................

I take my hat off to you
 
breezer said:
mr_chaela said:
I think you misunderstand, the circuit is not switching the supply to the PIR, it's switching the output from the PIR

your drawing did not make that bit clear, but yes, now you mentioned that bit....................

I take my hat off to you
thanks
 
I have a setup as in TTC's diagram and it works well (even if looking somewhat more complicated than the diagram) using a total of 4 lamps which all come on if triggered by either PIR. The idea of relays whilst workable sounds to be no advantage and I'd suggest that the problem lies within the PIR circuitry. Assuming the wiring within the PIR connector box is correct, you may have the PIRs too close to each other and/or pointing in a similar direction.
The slight delay in triggering is seen by the circuitry as the built-in "quick on and off switch" which allows creates a permanent supply to the lamp.
I may have misread some earlier posts (and apologies if I have), but am concerned by the notion of separate supplies to the system. The supply must come from a single point (MCBFCU etc). There must never be different sources as it would be possible to isolate one (and test it as safe) only for the whole to be energised by the tripping of the other PIR.
V
 

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top